Leukemia inhibitory factor and interleukin-11: cytokines with key roles in implantation.

Members of the interleukin-6 family of cytokines include leukaemia inhibitory factor (LIF), interleukin-6, interleukin-11, cardiotrophin, ciliary neurotropic growth factor, oncostatin M and the recently discovered cardiotropin-like cytokine (NNT-1). These ligands signal via heterodimeric receptors composed of ligand-specific alpha chains and the common signal-transducing subunit gp130. Gene targeting in mice provided the first indication of a role for interleukin 6 family cytokines in implantation with the generation of mice with a null mutation of the gene encoding LIF. LIF null female mice were infertile because of failure of blastocyst implantation. More recently, interleukin-11 signalling has been shown to be required for the uterine decidualization response. This review describes the insights into the role of interleukin-6 family cytokines in female fertility that have come from gene targeting experiments in mice.